IN THE PROCESS OF SHEDDING illusions over the past decade or so, we Americans have fallen into an unattractive habit of scapegoating.

Iquote from a recent book review by John Kenneth Galbraith:

"In the space of a few months in 1959 and 1960, [Allen] Dulles, as head of the CIA, showed himself to be a master of disastrous ineptitude. In those months he sent Gary Powers over the Paris Summit, helped overthrow the neutralist government of Souvanna Phouma in Laos . . . and was the man charge of the organization that was responsible for perhaps the greatest foul-up in our history, the Bay of Pigs."

Dulles did it. Or J. Edgar Hoover. Or some other wretch who must suffer for our sins. It is the devil theory of history or, as someone has said of the CIA, the notion that rogue elephants unaccountably appear in our happy land to bring shame to us all. It is hard for us to accept the possibility that such men and institutions have, in fact, been our good and faithful servants and that we have been their witting sponsors.

This impressive book by Thomas Powers addresses that possibility. It persuades me, beyond reasonable doubt, that the Central Intelligence Agency, by and large, has been a most careful servant of the American government and, by extension, the servant of us all.

In 1948, as the agency was being put together, its covert action unit was given a charter by the National Security Council. It authorized "propaganda, economic warfare; preventive direct action, including sabotage, anti-sabotage, demolition and evacuation measures; subversion against hostile states, including assistance to underground resistance groups, and support of indigenous anti-Communist elements in threatened countries of the free world." There was another stipulation. These activities should be carried out in such a way "that any U.S. government responsibility for them is not evident to unauthorized persons and that if uncovered the U.S. government can plausibly disclaim any responsibility for them."

This was a charter for dirty tricks. I suspect that if it had been put to a national referendum at the time, it would have met with the overwhelming approval of the American people.

It is clear, in any event, what Harry Truman and his Security Council expected of the agency, and it is clear from the evidence Powers assembles that those expectations were shared by every subsequent president of the United States. The covert interventions in Iran, Guatemala, the Congo, Chile, Cuba, Laos and elsewhere were not impulsive cowboy operations by mad agents. They were the deliberate policies of the American government.

When it comes to the assassination plots against foreign leaders, such as Lumumba and Castro, the question is a bit stickier. The Church Committee investigates those matters four years ago and came in with a verdict of case not proved. But the circumstantial evidence Powers assembles persuades me that the CIA was not acrint on its own.

As Powers writes, "talk about killing was common place" in Washington in the 1950s and 1960s. A West German general came to Allen Dulles, Richard Helms and others in 1952 with a proposal (which was rejected) for the assassination of Walter Ulbricht, the East German leader. At a State Department meeting in the mid-'50s, the subject was Gamal Abdul Nasser of Egypt. of whom Dulles said: "If that colonel of yours pushes us too far, we will break him in half." In November 1960, Undersecretary of State Livingston Merchant asked his colleagues of the Special Group overseeing covert operations if "any real planning had been done for taking direct positive action against Fidel, Raul and Che Guevara." Their demise, he suggested, would leave Cuba "leaderless and probably brainless." Later in that decade, Robert Murphy of the president's Foreign Intelligence Advisory Board, asked why the CIA hadn't killed Ho Chi Minh as a solution in Vietnam: "Ho is the problem, isn't he? Can't you fellows do something to get rid of him?"

The most damning illustration of White House involvement in affairs of this kind was the Kennedy Administration's determination to get Castro. The common view is that Ricahrd Bissell, who directed the CIA operation at the Bay of Pigs, was fired because that ill-concieve adventure failed.

"But this was only part of the explanation," Powers writes, "the public part, in fact, while the private part had to do with Bissell's continued failure to make progress in getting rid of Castro."

Bissell and others in the CIA were under constant and extreme pressure from the president and the attorney general, Robert Kennedy, to "get off their ass" and "do something" about Castro. That was the whole point of Operation Mongoose, in which Robert Kennedy was a prime mover. The details Powers assembles about this operation are fascinating; the reader can decide for himself who knew what.

The subtitle of this book is "Richard Helms and the CIA," But it is only incidentally about Helms and his fellow secret-keepers. Mostly it is a masterful portrait of an agency and its managers and of their relationship to the governments they served. Powers, who won a pulitzer Prize as a wire-service reporter, spent hours with Helms and other celebrated CIA figures. Why they talked to him at such length and with such candor is hard to say. But they did, and they have given Powers the materials for the finest book I have yet read on the CIA. The agency's managers do not always or even frequently appear in a flattering light. They were often amoral and servile. But, I think, more often than not they represented in thought and action the purposes of the governments that employed them. They found it hard to say, "no," to presidents and cabinet secretaries. t

In a sense, they were bootlickers, fascinated in intimidated by the presidency, like other bureaucrats of the federal establishment. "The primacy of presidents," Powers writes, "is the great fact in the CIA's daily round. If the president does not trust or value the Agency's product, then the paper it produces ceases to have weight in government councils and it might as well unplug its copiers, because it is only talking to itself. The first duty of the [director of Central Intelligence], then, not by statute but as a matter of practical reality, is to win the trust, the conficence, and the ear of the president."

And to keep the secrets. Above all, to keep the secrets: "On May 10, 1967, Helms went to the White House to give Lyndon Johnson the answers to the questions he'd been asked seven weeks earlier. The only account of that meeting is Helms' own. He says he described the [inspector general's] conclusions and that Johnson said:

"'Then you were not responsible for Trujillo,' No.' Correct answer. 'Deim?' No.' Correct answer. 'Castro, he's still alive, okay.' At the same meeting Helms also told Johnson about the mail interception program 'and some other things that were going on.' Johnson's response to that was equally laconic; he just nodded and said something along the line of, 'But be careful, don't get caught.'"